Unidirectional rotary electric switch



June 24, 1958 J. M. MARTIN 2,340,672

UNIDIRECTIONAL-ROTARY ELECTRIC SWITCH Filed May 22, 1956 INVENTOR AGENT JOSEPH M. MARTIN e 2,840,672 1C6 Patented June- 24, 1 958 UNIDIRECTIONAL ROTARY ELECTRIC SWITCH Joseph M. Martin, Sherman Oaks, Califl, assignor to Burroughs Corporation, Detroit, Mich., a corporation of Michigan Application May 22, 1956, Serial No. 586,446

8 Claims. (Cl. 200-155) The present invention relates to electrical switches of the unidirectional sequentially operated type and more particularly to a locking control for such or other type of switch.

In the use of unidirectional switches arranged for sequential operation in such complicated mechanisms as electronic computers, accounting and line controlled printing mechanisms, it is of vital importance that the sequence be not interrupted to thereby upset the precise cycle operations.

An object of the present invention is to provide a control for a rotary switch wherein the switch closing contactor is prevented from turning in a direction opposite to that required to close a circuit.

Another object is to provide a lock to prevent a unidirectional rotary switch from turning in other than a predetermined direction.

Another object is to provide a lock for association with unidirectional switches whether intended for either clockwise or counterclockwise rotation.

A further object is to provide a detent mechanism for switches arranged to formation in synchronism with the switch make and break assembly to permit free unrestrained turning of a contactor to close a circuit while also operative to prevent reverse turning of the contactor.

Further objects will appear hereinafter.

In the accompanying drawings:

Fig. 1 is an exploded view of the parts of a rotary switch control embodying one form of the present invention;

Fig. 2 is a side elevation as assembled;

Fig. 3 is a detail view in plan of the control element with a part broken away;

Fig. 4 is a section view taken on line 44 of Fig. 3; and

Fig. 5 is a fragmentary section taken on line 55 of Fig. 4.

Referring to the drawings, the switch control or movement limiting means of the invention is shown for example as an incorporated part of a rotaryunidirectional switch of the type wherein a rotatable contactor is concentrically arranged with respect to a plurality of terminal contacts and including a yielding means for holding the switch in any one of its sequential close circuit positions. As illustrative of this type of switch reference can be had to United States Letters Patent Nos. 2,012,492, 2,186,949 and 2,186,950.

For understanding the present invention the description of the switch will be limited to those related parts believed novel. These parts include the contactor operating spindle which is journalled in an externally threaded switch mounting bushing 11 for attachment to a suitable panel or the like. A locking clip 9 is disposed between the bushing 11 and a shoulder on the spindle 10 to prevent axial movement of the spindle under biasing action of a spring switch part juxtaposed to the non-rotatable detent plate 12. A switch plate 13 of insulating material is keyed to the spindle 10 and 2 carries the contactor ring and concentric row of fixed contacts including circuit wire connectors 13 as com,- mon to this type of switch. The switch plate 13 is supported by spacer posts 14 from the plate 12. The upper face of the plate 12 is provided with a circular row of rounded projections 15 having the spindle 10 as a center and juxtaposed to the path of travel of a pair of ball detents 16. The ball detents are carried by a rotatable ball retaining cage ring 17 which is connected to the spindle 10 for joint rotation therewith by means of a transverse strip 18 fixed to the spindle 10. The ring 17 is of spring material and, as assembled, biases the caged detents 16 to seat between any pair of projections corresponding to a selected closed circuit.

For the purpose of preventing the spindle 10 from turning in the opposite direction to its selected unidirection, the plate 12 is provided with a row of upstanding stops 20, concentric 'with respect to the projections 15, and forming a circular hill and valley path for a spring pressed keeper 21. The stops 20 lie respectively on the radii of the projections 15. The keeper 21 is slidably mounted in an arm 22 keyed to the spindle 10 and projecting radially therefrom to locate the lower end of the keeper 21 in operative relation to the row of stops 20. The upper end of the keeper 21 is provided with a head 23 seating upon the arm 22 and biased to stopengaging position by a flat spring 24 which is attached at its opposite end to the arm 22 to follow the turning motion thereof. The lower or stop engaging end of the keeper 21 is cut away on one side to provide a fiat face 25 opposite to a cam surface 26 on the other side. If the switch is to operate in a clockwise direction the keeper 21 will be in the position shown in Fig. 4, but if counterclockwise is the direction, the keeper21 will be turned to face the cam 26 in the opposite direction. When set for its unidirectional control the keeper 21 is locked against axial turning by a pin 27 projecting upwards from the arm 22 and seating in a recess 28 in the keeper head 23. The pin 27 also freely traverses a hole 30 in the spring 24 to avoid interference with the spring action. When the keeper 21 is set for counterclockwise locking by turning a half revolution it is fixed by the pin 27 seating in a recess 31 diametrically opposite to the recess 28.

In operation, and assuming the sequential closing of the switch circuits is clockwise as shown in the drawings, a turning of the spindle 10 to oil-switch position causes the ball detents 16 to ride up on their respective adjacent projections 15 while simultaneously the cam 26 on the keeper 21 engages a stop 20 to lift the keeper 21, against the pressure of the spring 24, to ride over the stop which cammed it upward. Further turning the spindle 10 closes a required circuit and causes the detents 16 to drop between the adjacent pair of projections 15, while simultaneously the spring pressed keeper 21 snaps in front of the next following stop 20. In this position of the keeper 21 its fiat face 25 is in the path of a reverse turning of the plate 12 to serve as a positive lock against counterclockwise turning of the switch spindle 10.

Where unidirectional sequential switch operation in a counterclockwise direction is desired the keeper 21 can be turned one half revolution to position the cam 26 opposite to the position here shown, while also rearranging its relation to the arm 22 by seating the pin 27 in the recess 30 to lock the switch against clockwise turning.

It will now be apparent that a novel control for rotary switches has been devised whereby a plurality of circuits can be sequentially closed by the turning of the switch spindle in one direction while locking the spindle against reverse turning in each closed circuit position.

What is claimed is:

1. A control for unidirectional rotary switches, coma circuit, means actuated by turning said-spindle in one direction for holding said switch in circuit closing position, a fixed stop means, a keeper carried by said spindle adapted to be intercepted by said fixed stop means, means mounting said keeper for sliding movement towards and away from said fixed stop means, spring means biasing said keeper toward said fixed stop means, a cam on the leading side of said keeper to shift said keeper past said stop means when said spindle is turned in one direction, and means on the trailing side of said keeper to abut said stop means to prevent shifting of said keeper when said spindleis turned in the reverse direction, whereby said spindle is locked against such reverse turning.

2'. A control according to claim 1 wherein said fixed "stop ,means is an arcuate row of fixed projections and spring pressed detents turnable with the spindle.

I 3. A control for unidirectional rotary switches, comprising a spindle for operating a switch to sequentially close and open a plurality of circuits, means actuated by turning said spindle in one direction for holding said ,spindle in circuit closing position, a circular row of stops, means mounting said stops with said spindle as a center 'and fixed against turning, each of said stops correspond- -ing to a circuit closing position, a keeper carried by said spindle, means mounting said keeper for sliding movement towards and away from said stop row, spring means biasing said keeper towards said stop row, a cam face on the leading side of said keeper to shift said keeper past a stop when said spindle is turned in one direction, and means on the trailing side of said keeper to abut a stop when said spindle is turned in the opposite direc- ,jtion whereby said spindle is locked against turning in 'said'opposi'tedirection.

4. A control for switches according to claim 3 wherein said keeper mounting means is an arm radially atprising a spindle for operating a switch to close and open tached to said spindle, and said keeper has a head seating on said arm to suspend said keeper.

5. A control for switches according to claim 4 wherein means prevents axial turning of said keeper.

6. A control for unidirectional rotary switches for sequential closing of electric circuits by rotating a contactor over fixed contacts through step-by-step turning of a spindle comprising means operated by turning of said spindle in one direction for yieldingly holding a circuit closed, and means carried by said spindle operative in said closed circuit position to prevent said spindle from turning in a reverse direction.

7. A control according to claim 6 wherein said reverse preventing means is a plurality of fixed stops, a keeper carried by said spindle and spring biased to ride over said stops in one direction of rotation of said spindle, and means on said keeper to prevent turning of said keeper in a reverse direction.

8. A control for rotary switches comprising a spindle, a bushing between the ends of said spindle forming a journal for said spindle, a fixed switch mounting plate carried by said bushing, a circular row of projections on one face of said plate, spring pressed means carried by said spindle to coact with said projection to hold said spindle in any switch position, a row of circular stops on said plate lace concentric to said projections, a keeper, means carried by said spindle to mount said keeper for sliding movement, a spring biasing said keeper towards said stop row, a cam face on said keeper to engage a stop and raise said keeper in one direction of rotation of said spindle, and a fiat face on said spindle opposite said cam face to engage a stop when said spindle is turned in the reverse direction to lock said spindle.

References Cited in the file of this patent UNITED STATES PATENTS 2,740,056 Parker et a1. Mar. 27, 1956 

